Centering intravascular filters and devices and methods for deploying and retrieving intravascular filters
An intravascular expandable filter which has centering members that work to center the filter in a body vessel, the centering member creating a zone at the radial extent of the filter substantially parallel to the longitudinal axis of the filter. A device to deploy the filter consisting of an inner sheath with radially expandable distal arms having slots in them to receive the elongate members of the filter. A device to receive the filter consisting of a member to push a central portion of the filter into a receiving portion of the device.
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This invention relates to intravascular filters for use in a body vessel lumen and devices and methods for retrieving intravascular filters.
BACKGROUNDIntravascular filters are used to capture and retain blood clots and other emboli. The emboli may be lysed while retained by the filter or it may be retrieved, usually with the filter. Occasionally it is desirable to use an intravascular filter for an extended period of time, perhaps two to four weeks, and then retrieve it. When an intravascular filter is deployed, it is desirable to properly center the filter for maximum effectiveness and to minimize deleterious effects. Many previous filter deployment techniques consist essentially of inserting a catheter into the vasculature to the desired location and then pushing the filter from the end of the catheter. It is sometimes difficult to position the filter in the center to adjust the filter once it is in position. These devices and techniques provide minimal opportunities for adjusting the filter during or after deployment.
SUMMARYOne embodiment of the invention pertains to intravascular filters which are easier to properly center in the body vessel lumen. One example filter includes elongate members which extend radially out from a central member in a first direction. At the end of the elongate members are centering members that extend substantially parallel to the vessel walls and to the central longitudinal axis of the filter. The centering members may extends from the elongate members in a second direction opposition the first direction, the first direction, or both directions. Anchoring members may be positioned on one or more ends of the centering members. One example embodiment includes a bulge between the elongate members and the parallel portions of the centering members that may extend radially beyond the parallel portions.
Another example embodiment provides centering members which extend radially from the central filter member and may extend in the first direction. The centering members may be shorter than the elongate members and may extend radially outwardly more sharply than the elongate members. The centering members may also be substantially parallel to the elongate members and joined to the central member at a position spaced apart from the position that the central members joined at. The centering members may include atraumatic ends such as spheres or may include anchoring members such as barbs.
Another embodiment of the invention pertains to a device for deploying an intravascular filter. The device may include a first sheath having a central lumen and slots disposed around the central lumen for positioning and retaining the elongate members of the filter. The device may include a guidewire or other means for pushing the filter from the sheath. The device may also include a second sheath disposed around the first sheath, the first sheath having a radially expandable plurality of arms at the distal end. Each arm may have a slot therein for the retention and guidance of a filter. The filter may be installed by extending the first sheath distally from the second sheath so that the arms expand and thereby guide the elongate members of the filter to the desired locations.
Another embodiment of the invention pertains to a device for withdrawing an installed filter from a body vessel lumen. The device may include a capturing member which has a cylindrical lumen and an elongate member for pushing the central portion of the filter into the capturing member. One example embodiment includes a capturing member on an elongate rod and a substantially straight pushing member. The capturing member may be introduced from the upstream side of an installed intravascular filter and maneuvered through the filter so that an open end of the capturing member lumen is positioned proximate the central portion of the filter. The pushing member may then be used to push the filter into the capturing member. As the filter is pushed into the capturing member, the radially expanded elongate members of the filter are compressed. The filter may then be removed or moved into a catheter and then removed. Another example embodiment includes a pushing member which has a distal end that may be substantially parallel to the body of the pushing member and facing proximally. It has a configuration similar to a hook. This example embodiment may be best suited for withdrawing the filter from downstream. The pushing member is maneuvered so that the distal end is able to push on the central member of the filter. The capturing member is maneuvered to the opposite side of the central filter member. The pushing member can then be withdrawn to urge the filter into the capturing member. Alternatively, the pushing member can be held in place to prevent the filter from moving and the capturing member can be drawn over the filter.
The above summary of some embodiments is not intended to describe each disclosed embodiment or every implementation of the present invention. The figures and detailed description which follow more particularly exemplify these embodiments.
BRIEF DESCRIPTION OF THE DRAWINGSThe invention may be more completely understood in consideration of the following detailed description of various embodiments of the invention in connection with the accompanying drawings in which:
The following detailed description should be read with reference to the drawings, in which like elements in different drawings are numbered identically. The drawings which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of the invention.
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Numerous advantages of the invention covered by this document have been set forth in the foregoing description. It will be understood, however, that this disclosure is, in many respects, only illustrative. Changes may be made in details, particularly in matters of shape, size, and arrangement of parts or order of steps without exceeding the scope of the invention. The invention's scope is, of course, defined in the language in which the appended claims are expressed.
Claims
1. An intravascular filter, comprising:
- a center element;
- a plurality of elongate elements extending in a first direction from the centering element, each elongate element having a first end joined to the center element at a first longitudinal position and a second end;
- a plurality of anchoring elements connected to the second ends of the plurality of elongate elements; and
- a plurality of centering elements having a plurality of vessel wall contacting regions disposed in the first direction from the center element.
2. The filter of claim 1,
- further comprising a central longitudinal axis,
- wherein a first portion of each of the plurality of vessel wall contacting regions is substantially parallel to the central longitudinal axis.
3. The filter of claim 2, wherein the plurality of centering elements are disposed at the second ends of the plurality of elongate elements.
4. The filter of claim 3, wherein the plurality of centering elements are disposed between the plurality of elongate elements and the plurality of anchoring elements.
5. The filter of claim 4, wherein the plurality of vessel wall contacting regions extend from the second ends of the plurality of elongate elements in a second direction opposite the first direction.
6. The filter of claim 5, wherein the anchoring elements are disposed at ends of the plurality of anchoring elements, the ends being the ends in the second-most direction.
7. The filter of claim 4, wherein the plurality of vessel wall contacting regions extend from the second ends of the plurality of elongate elements in the first direction and in a second direction opposite the first direction.
8. The filter of claim 4, wherein the plurality of vessel wall contacting regions extend from the second ends of the plurality of elongate elements in the first direction.
9. The filter of claim 8, wherein each of the plurality of centering elements comprise a second curved portion, the second curved portion disposed between the plurality of elongate members and the first portions.
10. The filter of claim 9, wherein the second curved portion extends radially beyond the first portions.
11. The filter of claim 9, wherein the plurality of anchoring elements are disposed at ends of the plurality of anchoring elements in the first-most direction.
12. The filter of claim 1, wherein the plurality of centering elements extend radially outward from the center element.
13. The filter of claim 12, wherein the vessel contacting regions comprise a sphere.
14. The filter of claim 12, wherein the plurality of centering elements extend radially outward more sharply than the plurality of elongate elements.
15. The filter of claim 12, wherein each of the plurality of centering elements have a first end joined to the center element at a second position spaced longitudinally apart from the first position.
16. The filter of claim 15, wherein each of the plurality of centering elements is substantially parallel to one of the plurality of elongate elements.
17. The filter of claim 16, wherein the plurality of vessel wall contacting regions comprise anchoring elements.
18. A deployment device for an expandable filter having a plurality of elongate elements, comprising:
- a first sheath having a central lumen extending from a first end to a second end and a plurality of slots for positioning the plurality of elongate elements; and
- a filter deployment element.
19. The device of claim 18, wherein the plurality of elongate elements and the plurality of slots are equal in number.
20. The device of claim 18, wherein the filter deployment element comprises an elongate element slidably disposed in the central lumen of the first sheath.
21. The device of claim 18, further comprising a second sheath slidably disposed over the first sheath, wherein the filter deployment element comprises a radially expandable portion of the first sheath.
22. The device of claim 21, wherein the first sheath radially expandable portion comprises a plurality of arms, each arm having a first free end and a second joined end.
23. The device of claim 22, wherein a plurality of the arms comprise the plurality of slots.
24. The device of claim 22, wherein the arms are in an expanded position when unconstrained.
25. The device of claim 21, wherein the first sheath comprises a first stop and the second sheath comprises a second stop, wherein when the first stop is against the second stop, the first sheath radially expandable portion is expanded.
26. A filter retrieval device for retrieving an expandable filter having a central portion with elongate members extending radially therefrom in a first direction, comprising:
- a capturing member having a first open end spaced apart from a second open end and a retrieval lumen therebetween; and
- a elongate device for urging the filter into the capturing member by pressing the central portion of the filter.
27. The device of claim 26, wherein the capture member further comprises an elongate rod having a first end attached to the second open end of the capturing member, wherein the elongate rod does not obstruct the retrieval lumen.
28. The device of claim 26, wherein the elongate device has a distal end that faces proximally.
29. The device of claim 28, wherein the distal end is substantially parallel to a proximate proximal portion of the elongate device.
30. A filter retrieval device, comprising
- a guidewire having a distal end; and
- a plurality of retrieval prongs attached to the distal end of the guidewire, the plurality of retrieval prongs arranged radially around a central cavity having a distal opening for receiving a portion of a filter, each retrieval prong having a distal end movable between a first position and a second radially expanded position and having a distal inward lip.
31. The filter retrieval device of claim 30, wherein each of the retrieval prongs is flexible.
32. The filter retrieval device of claim 30, further comprising a flexible joining member disposed between the plurality of retrieval prongs and the guidewire.
33. The filter retrieval device of claim 30, further comprising a catheter having a distally open lumen sized to fit over the retrieval prongs in the first position and retain the retrieval prongs in the first position.
Type: Application
Filed: Feb 13, 2004
Publication Date: Aug 18, 2005
Patent Grant number: 7323003
Applicant:
Inventor: Brian Lowe (Zimmerman, MN)
Application Number: 10/779,152